Temporal and within-plant distribution of the parasitoid and predator complexes associated with Acyrthosiphon pisum and A. kondoi (Homoptera: Aphididae) on alfalfa in Japan

Abstract

Seasonal abundance and within-plant distribution of Acyrthosiphon spp. and their natural enemies were investigated on alfalfa in Obihiro, Hokkaido, Japan in 2001. Densities of A. pisum and A. kondoi peaked in early June. Coccinellid and syrphid predators appeared to respond to aphid numbers and were synchronized with aphid populations. Two species of braconid (aphidiine) parasitoids (Aphidius ervi and Praon barbatum) were collected. Parasitism rates for each aphid species were variable through the season, but the estimated number of parasitized aphids reached a peak at the same time as overall aphid densities. After the first harvesting of alfalfa (14 June) aphid densities became very low, and coccinellid and syrphid predators were not found. In contrast to the coccinellid and syrphid predators, the heteropteran predators, Nabis stenoferus and Orius spp. became common during summer. Aphids, immature parasitoids (live parasitized aphids and mummies), Coccinella septempunctata and syrphids occurred more on the upper parts of alfalfa stems than on the lower parts, but this trend was not found for Hippodamia tredecimpunctata. The temporal and spatial distributions of members of the aphidphagous guild are likely to influence natural enemy-aphid relationships and intraguild interactions.

Seasonal dynamics of: the pea aphid, Acyrthosiphon pisum (Harris), its natural enemies the seven spotted lady beetle Coccinella septempunctata Linnaeus and variegated lady beetle Hippodamia variegata Goeze, and their parasitoid Dinocampus coccinellae (Schrank)

“…The current findings of population fluctuations of lady beetles are concurrent with previous studies (Summers 1976;Wheeler 1977;Nakashima and Akashi 2005). Summers (1976) and Wheeler (1977) observed that populations of lady beetles in an alfalfa field in California and New York were high in May and September.…”

“…It seems that a reduction in aphid populations along with the higher temperatures during this period had a negative effect on the densities of natural enemies as well. This issue has also been addressed by Nakashima and Akashi (2005).…”

“…Population dynamics of alfalfa aphids and their natural enemies have been studied by many researchers in Iran as well as in other countries (Grimm 1972;Wheeler 1974;Neuenschwander et al 1975;Summer 1976;Harper 1978;Gonzalez et al 1979;Aeschlimann 1981;Monajemi and Esmaili 1981;Takahashi and Natio 1984;Rasoulian 1985;Nakashima and Akashi 2005;Rakhshani et al 2006).…”

Effects of intra and interspecific interactions on the survival of two predatory ladybirds (Coleoptera: Coccinellidae) in relation to prey abundance

“…Menge and Sutherland, 1987;Begon et al, 1996). Intraguild predation is common among arthropods in agricultural (Rosenheim et al, 1993(Rosenheim et al, , 1995Cisneros and Rosenheim, 1997) and natural ecosystems (Moran and Hurd, 1994;Snyder and Hurd, 1995); therefore, intraguild predation is thought to be an important factor affecting population dynamics and community structure in several taxa of predatory arthropods (Polis et al, 1989;Spence and Carcamo, 1991;Polis and Holt, 1992;Fincke, 1994;Wagner and Wise, 1996; Holt and Polis, 1997;Mizell, 2007;Montserrat et al, 2008).Many species of predatory arthropods are attracted to sites where aphids are abundant (Sakuratani, 1977;Aalbersberg et al, 1988;Winder et al, 1994;Wyss, 1995;Nakashima and Akashi, 2005;Alhmedi et al, 2007). In these aphidophagous guilds, intraguild predation often occurs and its incidence depends on prey abundance and the developmental stages and species of the predator involved (Takahashi, 1989;Agarwala and Dixon, 1992; Rosenheim et al, 1993;Cisneros and Rosenheim, 1997;Dinter, 1998;Lucas et al, 1998;Obrycki et al, 1998;Phoofolo and Obrycki, 1998).…”

Temporal genotypic diversity of Schizaphis graminum (Rondani 1852) (Hemiptera: Aphididae) in a black oats (Avena strigosa) field

“…When aphid colonization is at the beginning, there is no significant parasitism and predation. As a consequence, the founder population will have predominance at temporal and spatial scale (Nicol et al, 1997;Nakashima and Akashi, 2005). The second most common genotype, Sg2, was only detected in the samples collected in June, but already detected with higher frequency at this month.…”